Indicating device



Patented May 31, 1949 Jack D. McCullough, Detroit, Mich., assignor toChrysler Corporation, Highland Park, Mich., a

corporation of Delaware Application June 4, 1945, Serial No. 597,469

This invention is related to electrical apparatus, and particularly todevices used for measurement and observation of certain phenomena. Inits specific embodiment, the invention is used jointly with a cathoderay oscillograph which, in turn, is used for indicating visuallytransients or other forms-of response. Where desired, photographicrecords of the phenomena may be made by photographing the oscillographpattern in known manner.

Particularly, the apparatus herein to be described is concerned withproviding a visible means for determining and indicating the performanceof spark plugs in gasoline engines of all types.

The present invention is concerned particularly with the development ofa device which provides a relatively cheap and portable means which iswell adapted to be used for servicing aircraft engines and, in fact, allforms of automotive gasoline engines. Accordingly, the apparatus isparticularly useful at airports, garages and manufacturing plants forthe purpose of indicating the exact performance of the sparking system,and making it a relatively simple matter not only to detect anddetermine imperfect performance, but actually to observe the exactfunctioning of the particular spark plugs so that any such plugs notfunctioning correctly may be removed and replaced. In this way it ispossible promptly to note and observe the exact seat and cause ofimperfect engine operation.

An object of the present invention is the application of an oscillographto an ignition system for noting the performance of spark plugs in theignition system. By my invention I am enabled to observe the performanceof all the spark plugs. I may apply the oscillograph to the primary sideof the ignition system.

A further object of the invention is toprovide improvementsin controleffected by the vertical and horizontal deflecting means serving tooperate upon the cathode ray beam in a. cathode ray oscilloscope. Moreparticularly, the control is applied to an oscilloscope indicatingsimultaneously the performance of various spark plugs in an ignitionsystem and is effective to provide synchronism between the deflection ofthe cathode ray and discharge of the spark plug andto enable an observerreadily to determine which of the spark plugs in the ignition systemproduces each and every pattern to be seen in the oscilloscope. Thiswill involve not a connection from the ignition system to one of thedeflecting means but the setting up of impulses in the deflecting 6"Claims. (01. -183) means through inductive action of the ignitionsystem.

Other objects will appear from the disclosure.

In the drawing there has been schematically illustrated a conventionalignition system, which y omprise the energy source, such as the batteryH having one terminal thereof grounded at l2, and the conventionallyrepresented breaker points, shown for illustrative purposes as theswitch l3,and their conventional capacitors, the

transformer comprising the primary winding l9 and thesecondary winding2|, of which one terminal of the primary is also grounded at m and ofwhich the outer terminal of the secondary 2| connects by way of theconductor 23 to the rotating armature 25 of a distributor l5. Variouscontacts, shown by the numerals I through 6, inclusive, of thedistributor l5 are intended to connect to different cylinders of thecomplete motor, with the numerals adjacent each terminal point beingindicated in a conventional manner relative to the rotation of thedistributor arm 25. The illustration is intended to show one suitableform of firing order, which it may be assumed follows the designationsl, 5, 6, 3, 2, and 4, although it is to be understood that this ismerely given for the purpose of illustration, as is likewise theillustration of the assumed six cylinders, for it is obvious that inautomotive engines, the number may vary within wide limits, andparticularly for aircraft engines the numbers of cylinders and resultantdistributor points are ve y substantially increased.

There has been shown only a single spark plug element I! to which energyis supplied by way of the conductor 2! connecting to the upper terminalthereof in known manner. It will be appreciated, however, that otherspark plugs (not shown) connect to each of the other oints 5, 6, 3, 2,and 4 in substantially like manner. The energy supplied by way of thebreaker points, the transformer and the distributor to the spark plugsis discharged across the gap provided between the points 28 and 29,which are also shown in purely conventional manner.

In order that the spark discharge may be measured and observed, controlis exerted over the deflection of the cathode ray beam 39 within acathode ray oscilloscope 3| in a manner later to be explained. Theoscilloscope tube 3| comprises the usual electron gun 33, represented inpurely schematic form, which is adapted when suitably energized byappropriate operating voltages from sources not shown, to produce anelectron beam 39 which is'directed longitudinally of the tibe to strikeagainst a luminescent end wall target or screen, conventionallyrepresented at 4 i where it produces a luminous trace due to impact.

In the path of the beam $9 as it moves from the electron gun 33 to thetarget or screen 4i, suitable deflecting means are provided. These(reflecting means may be either electrostatic or electromagnetic, or acombination of these two forms, but for illustrative purposes. thedrawing shows the horizontal deflection as provided byelectrostatiqmeansconsisting of two deflecting plate electrode members85, and the vertical deficciion likewise is assumed to be controlled byt-:c electrostatic deflecting plate pair 31. For the purpose ofproviding horizontal deflection of the elccron beam 39 within the tube31, a horizontal deflection control generator 43 has been provided. Thisgenerator preferably consists merely of the usual form of relaxationoscillation generator in which a charge is built up across a condenserelement charged through an appropriate form of constant current charginginstrumentality, which is dischargeable at times when an associateddischarge tube is suitably energized or triggered under the control of aphenomenon associated with the ignition circuit.

The discharge tube may be of either of the high vacuum or the gaseoustype, which is well known in the art. When the deflecting plateelectrode pair 35 is connected so that one electrode element isconnected to be energized in accordance with the charge upon the storagecondenser of the horizontal deflection control generator 43. and theother plate is connected to ground at [2, for instance, the potentialacross the condenser of the relaxation oscillator combination will be ameasure of the deflection. If now a deflection of the beam 39in the tube3! can be initiated by suitably energizing or triggering the element 43under the influence of the transient to be observed. it is apparent thatsynchonism may be established between deflection of the cathode ray anddischarge of the spark plugs.

A high impedance voltage divider comprising resistance elements 41 and48 is connected between the ground I! and a junction point 49 betweenthe primary winding i9 and the secondary winding 2 i A conductor 50leads from a junction point 5| between resistance elements 41 and 48 toone side of the vertical deflecting means 31. The other side of thevertical deflecting means is connected to the ground [2. In this waycontrol of the vertical deflecting means is effected from the primarywinding IQ of the transformer. The voltage across the primary winding l9appears each time a spark occurs in any of the plugs of the ignitionsystem, and thus a vertical deflection of the cathode ray beam will beproduced on the luminescent target or screen 4 i In order that thecomplete system may be properly synchronized and locked in step with theoperation of the system, the horizontal deflection control generator isnow synchronized through induction produced by current flowing in theline 21 leading to any of the spark plugs H. An electromagnetic pick-upor current transformer 52 has a removable cross arm 53, and a permanentend cross arm 54. The conductor 21 extends through the space between thearms 53 and 54. A conductor 56 is coiled around the arm 54 as indicatedat 51 and leads from ground to the horizontal deflection controlgenerator. A conductor leads from the generator to one side of thehorizontal deflecting means 35, the other side being connected to theground l2. The use of the magnetic pick-up 52 not only eflects-gnchronization of the system but also enables an observer to determinewhich pattern in the screen 41 is associated with a particular lug. Thepattern of the plug having the conductor 21 with which the magneticpick-up is associated is at one end of the screen, conventionally, theleft end, and the other patterns will follow in order to designate theplugs following in the firing order after the particular plug. Forinstance, the magnetic pick-up is associated with the conductor for plugNo. 1, and the order of plugs following thereafter is 56-3- 2-4. Thus,as indicated, the pattern at the left end of the screen is for plug No.l, and the other patterns are in order from left to right for plugs Nos.5-6-3--2--4.

I claim:

1. In combination, a multi-cylinder internal combustion engine includingan ignition system comprising a primary and secondary transformerwinding, a contact making and breaking element, a distributor, sparkplugs of a number corresponding to the number of cylinders in theengine, and conductors leading from the distributor to the spark plugs,a cathode ray oscilloscope including means for developing a cathode rayscanning beam and a pair of deflecting means for deflecting saidscanning beam in each of two mutually perpendicular directions relativeto an observation target, a connection from one winding of saidtransformer to one of said deflecting means for deflecting said cathoderay beam in one of its directions of deflection, and means forgenerating repetitive deflections of the developed cathode ray beam inthe other of said directions at a frequency equal to the frequency ofoperation of the contact making and breaking element divided by thenumber of engine cylinders, said last mentioned means including acurrent transformer associated with a conductor leading to one sparkplug and means operatively connecting the current transformer and thesaid other of said deflecting means.

2. In combination, a multi-cylinder internal combustion engine includingan ignition system comprising a primary and secondary transformerwinding, :1 contact making and breaking element, spark plugs of a numbercorresponding to the number of cylinders in the engine, and conductorsleading from the distributors to the spark plugs, a cathode rayoscilloscope including means for developing a cathode ray scanning beamand a pair of deflecting means for deflecting said scanning beam in eachof two mutually perpendicular directions relative to an observationtarget, a connection from one winding of said transformer to one of saiddeflecting means for deflccting said cathode ray beam in one of itsdirections of deflection, and means for generating repetitivedeflections of the developed cathode ray beam in the other of saiddirections at a frequency equal to the frequency of operation of thecontact making and breaking element divided by the number of enginecylinders, said last mentioned means including an electromagnetic pickupassociated with a conductor leading to a spark plug for causingelectrical impulses in the conductor to induce impulses in the saidother defleeting means.

3. In an assembly comprising an ignition system for an internalcombustion engine comprising primary and secondary transformer windings,a contact making and breaking element, a distributor, spark plugs, andconductors leading from the distributor to the spark plugs. a cathoderay oscilloscope including means for developing a cathode ray scanningbeam and means for deflecting said seaming beam in each of two mutuallyperpendicular directions relative to an observation target, thecombination with the oscilloscope, of means for eflecting control of thedeflection of the cathode ray beam in one of the mutually perpendiculardirections from the primary side of the ignition system, means forcontrolling deflection of thecathode ray beam in the other of themutually perpendicular directions, and circuit forming means includingterminal portions and an inductive device connectingly therebetween fortriggering the last mentioned means by induction from the conductorleading from the distributor to a spark plug, said terminal portions andinductive device bein adapted for operation in physically and/orinsulatedly spaced relation to all parts of the aforesaid conductor.

4. An analyser adapted for use with an ignition system including adistributor, a plurality of engine spark plugs, and conductors leadingfrom the distributor to the spark plugs, said analyser comprising acathode ray oscilloscope including means for developing a cathode rayscanning beam and a pair of deflecting means for deflecting saidscanning beam in each of two mutually perpendicular directions relativeto an observation target, means for associating one deflecting meanswith the ignition system on the side of the distributor away from thespark plugs to eiiect the deflection of the scanning beam in one of thetwo mutually perpendicular directions and to make all spark plugsparticipate equally therein, and a current transformer associated withthe other deflecting means and coupled with the conductor connecting thedistributor and a certain spark plug so as to respond by induction tocurrent impulses in the conductor and thereby to initiate the deflectionof the scanning beam in the other of the two mutually perpendiculardirections for cooperating with the first mentioned associating means insimultaneously presenting indications of performance by all spark plugsand for enabling the identification of the various indications ofperformance with the various spark plugs.

5. An analyser adapted for use with an ignition system comprisingprimary and secondary. transformer windings, a distributor, a pluralityof engine spark plugs, and conductors leading from the distributor tothe engine spark plugs, said analyser comprising a cathode rayoscilloscope including means for developing a cathode ray scanning beamand a pair of deflecting means for deflecting said scanning beam in eachof two mutually perpendicular directions relative to an observationtarget, means for associating the deflecting means with one transformerwinding to effect the deflection of the scanning beam in one of the twomutually perpendicular directions and to make all spark plugsparticipate equally therein, and a current transformer associated withthe other deflecting means and coupled with the conductor connecting thedistributor and-a certain spark plug so as to respond by induction tocurrent impulses in the conductor and thereby to initiate the deflectionof the scanning beam in the other of the two mutually perpendiculardirections for cooperating with the first mentioned associating means insimultaneously presenting indications of performance by all spark plugsand for enabling the identification of the various indications ofperformance with the various spark plugs.

6. An analyser adapted for use with an ignition system comprisingprimary and secondary transformer windings, a distributor, and conductors leading from the distributor to a primary of engine spark plugs,said analyser comprising a cathode ray oscilloscope including means fordeveloping a cathode ray scanning beam and a pair of deflecting meansfor deflecting said scanning beam in each of two mutually perpendiculardirections relative to an observation target, means for associating thedeflecting means with the primary transformer winding to effect thedeflection of the scannin beam in one of the two mutually perpendiculardirections and to make all spark plugs participate equally therein, anda current transformer associated with the other deflecting means andcoupled with the conductor connecting the distributor and a certainspark plug so as to respond by induction to current impulses in theconductor and thereby to initiate the deflection of the scanning beam inthe other of the two mutually perpendicular directions for cooperatingwith the first mentioned associating means in simultaneously presentingindications of performance by all spark plugs and for enabling theidentification of the various indications of performance with thevarious spark plugs.

JACK D. MCCULLOUGH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain Aug. 17, 1944 Certificate ofCorrection Patent No. 2,471,968. May 31, 1949.

JACK MCCULLOUGH It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction asfollows:

Column 6, line 19, claim 6, for the Word primary read plurality; andthat the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOfiice.

Signed and sealed this 8th day of November, A. D. 1949.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

